 /*******************************************************************************
  * Copyright (c) 2000, 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.indexing;

 class ObjectHeader implements Insertable {

     public static final int SIZE = 4;
     private static final int HeaderTagValue = 0xFFFF;
     private static final int HeaderTagOffset = 0;
     private static final int ObjectLengthOffset = 2;
     private int objectLength;

     /**
      * ObjectHeader constructor comment.
      */
     public ObjectHeader(byte[] buffer) throws ObjectStoreException {
         if (buffer.length != SIZE)
             throw new IllegalArgumentException ();
         Buffer buf = new Buffer(buffer);
         if (buf.getUInt(HeaderTagOffset, 2) != HeaderTagValue) {
             throw new ObjectStoreException(ObjectStoreException.ObjectHeaderFailure);
         }
         this.objectLength = buf.getUInt(ObjectLengthOffset, 2);
     }

     /**
      * ObjectHeader constructor comment.
      */
     public ObjectHeader(int objectLength) {
         this.objectLength = objectLength;
     }

     public int getObjectLength() {
         return objectLength;
     }

     public byte[] toByteArray() {
         Buffer buf = new Buffer(SIZE);
         buf.put(HeaderTagOffset, 2, HeaderTagValue);
         buf.put(ObjectLengthOffset, 2, objectLength);
         return buf.get();
     }
 }

